Glass fiber yarns and compositions used in the manufacture of same



GLASS FIBER YARNS AND COMPOSITIONS USED IN THE MANUFACTURE OF SAME Alfred Marzocchi, Manville, R.I., Marcel R. Alexander, deceased, late of Central Falls, R.I., by Jeanne E. Alexander, administratrix, Central Falls, R.I., assignors to Owens-Corning Fiberglas Corporation, Toledo, Ohio, a corporation of Delaware.

No. Drawing. lFiled Ma 23, 1957, Ser. No. 661,027

14 Claims. 01. 28-80) This invention relates to the treatment of glass fibers in the manufacture of yarns and it relates more particularly to yarns formed of glass fibers having a size on the surfaces thereof which improves the processing and performance characteristics of the yarns and fabrics formed thereof.

It is an object of this invention to produce yarns of glass fibers sized with a composition that improves the processing and performance characteristics of the glass fibers and fabrics formed thereof and it is a related object to provide a new and improved sizing composition for use in same.

Another object of this invention is to provide a composition for use with glass fibers in the manufacture of yarns and fabrics which enables utilization of lower cost fiber systems in the manufacture of such yarns and fabrics thereby to decrease the cost of the yarns and products formed thereof; which improves the flexure and strength characteristics of the yarns and fabrics formed thereof; which improves the efficiency in the formation and twisting of the y'arns into sized glass fibers; which enhances the subsequent coating operation of the yarns to enable a wider variety of resinous materials in the form of plastisols or other coating compositions to be employed with the glass fibers with an improved bonding relationship between the resinous material and the sized glass fiber surfaces; which improves the water resistance of the glass fiber yarns; which improves the abrasion resistance of the glass fiber yarns; which improves the softness of the glass fiber yarns; which embodies a desired balance between lubricity and bonding to enable the yarns of glass fibers to be twisted, intertwisted and plied without difficulty, especially under wet conditions, and which decreases the fuzziness caused by the loose ends and tight twisting of the glass fibers in yarnformation thereby to enhance its utilization in the fabrication of textiles and other fabrics, and which enhances the weaving and braiding characteristics of multiple end yarns for the preparation of industrial fabrics and electrical insulations.

The concepts 'of this invention are embodied in the treatment of glass fibers employed in yarn formation with a size composition'embodying an oil-in-water emulsion system containing a combination of film formers balanced to enable the glass fibers to retain their individual characteristics during their initial processing under wet conditions, as in the formation of strands and bundles and in the twisting or intertwisting of the glass fiber strands and bundles in yarn formation. Upon heat treatment subsequent to processing into strands and yarns, the combination of elements provides a desired interbonding relationship as between the fibers and filaments to produce a yarn having exceptionally high strand integrity to enable enhanced performance of the yarn in subsequent coating, weaving or processing operations without the necessity for removal of the size or without the necessity of subsequent treatments.

The various concepts of this invention will hereinafter 2,958,114 Patented Nov. 1 19,60

be set forth by reference to a specific formulation of a size composition for application to glass filaments in forming for the manufacture of a new and improved yarn and fabrics formed thereof.

EXAMPLE 1 Composition 7 3.0 percent by weight oil modified alkyd resin (Aroplaz 1400Archer-Daniels Midland Co.) 2.0 percent by weight unpolymerized epoxy resin (G62-Rohm & Haas Co.) 1.5 percent by weight stearato chromic chloride 1.0 percent by Weight gelatin .15 percent by weight surface active agent (aryl alkyl polyether alcohol) (Triton X-Rohm & Haas Co.) 92.80 percent by weight water EXAMPLE 2 Formulation The oil modified alkyd resin, the unpolymerized epoxy resin and the Triton X-lOO are weighed into a tank fitted with a suitable mixer, such as an Eppenbach mixer. The gelatin, preferably in the form of a 5% solution, is added in the desired amount to the material in the tank with concurrent mixing after which the remainder of the water is added slowly to complete the emulsion which thickens at first and then thins upon further additions of water.

The stearato chromic chloride is prepolymerized by adding it to three times its volume of boiling water and the mixture is then added to the emulsion system previously formed of'the other materials;

The formed aqueous system, having a pH between 2-3, is exceptionally stable and will require no further agitation for maintaining the desired distribution of materials in commercial application.

EXAMPLE 3 Processing The composition formed by Examples 1 and 2 can be applied to the filaments of glass fibers in forming as they are gathered together to form strands or bundles, as in the conventional process for producing continuous fibers. For such purpose, use may be made of a wiper pad, roll applicator and the like. It is preferred to apply the size composition onto the glass fiber surfaces at' room temperature. However, slightly elevated temperatures insufficient to cause advancement of any of the materials in the'size composition may be employed, such as a temp'erature'below 200 F. v

The size composition applied to the glass fiber surfaces should be allowed to air dry prior to further processing of the fibers as by twisting or intertwisting and the like to form yarns. Air drying for a time greater than six hours is usually suificient although it is desirable to air dry for a time ranging from 12 to 24 hours to eliminate most if not all of the volatiles.

After drying, the strands of sized fibers can be twisted or intertwisted into yarns without difficulty because of tlielability of the fibens to shift as individual elements in the fabricated system while continuing to be protected by the film forming materials in the size composition which provides the desired balance between lubricity, bonding and protection for processing. The formed yarns are treated to advance the materials to a cured stage. In the system described, advancement will be caused to take place sufficiently even without catalyst at temperatures in excess of 250 R, such for example as by heating the yarns of sized fibers for from 10120 20 hours at a temperature within the range of 250- 350 F.

With catalyst, such for example as a peroxide (benzoyl peroxide or the like), the composition can be air cured or cured more rapidly at elevated temperature or at lower temperature. a 7

Illustrative of the oil modified alkyd resins are cocoanut oil modified alkyd resins and soybean oil modified alkyd resins such as are formed by the reaction of phthalic anhydride and glycol or the like condensation reaction products of a polycarboxylic acid and polyhydric alcohol but preferably the reaction product of an oil and the reaction product of a dicarboxylic acid and dihydric alcohol. Though not equivalent, use can be made as the film forming component of other water insoluble film forming materials, such as polymerized oils as represented by linseed oil, chinawood oil, oiticica oil and the like, alkyd resins, polyacrylic acid resins and polyalkyl acrylates, epoxy resins, phenol formaldehyde resinous systems, diallyl phthalates and the like, plasticized and unplasticized, wherein the preferred plasticizer is an unpolymerized epoxy resin as represented by Paraplex G-62 of the Rohm & Haas Co.

The oil modified alkyd resins or other film forming water insoluble material may be employed in the composition in an amount within the range of 1-5 percent by weight of the treating composition. The plasticizer component, when present, can be used in an amount ranging from to equal parts by weight of the water insoluble film forming component such as the oil modified alkyd resin.

The gelatin component represents the other film forming material in the described improved size composition. The gelatin component present in an amount of about 0.5 percent by weight in the treating composition can be employed in an amount within the range of 0.1-1.0 per cent by weight. In the described combination, the gelatin component is instrumental in the development of a peculiar but desirable property of enabling the fibers to withstand wet twisting so as to permit wet processing of the fibers into the yarns and strands formed thereof. As the gelatin component, use can be made of such other derivatives as chrome glue chrome tanned hides and the like gelatin components. Although not equivalent with respect to the wet processing characteristics developed, other water soluble colloids can be used, as represented by glue, starch, polyvinyl alcohol, polyvinyl pyrollidone, casein, alginates, methyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, and the like. Such other materials may be employed in amounts corresponding to that of the gelatin, depending of course upon the molecular weight and the viscosity characteristics of such other materials.

The following will illustrate a formulation embodying the features of this invention in which use is again made of an oil modified alkyd resinous system but in which a water soluble [fatty acid amine is employed in combina tion with the oil modified alkyd resin and film former in the size composition:

EXAMPLE 4 Composition 3.0 percent by weight soybean oil modified alkyd resin 5.0 Percent by weight unpolymerized epoxy resin (Paraplex G62-Rohm & Haas Co.).

5.0 percent by weight stearato chromic chloride 0.15 percent by weight polyglycol ester of a fatty acid 0.15 percent by weight of the condensation product of tetraethylene pentamine with fatty acid neutralized with acetic acid (Cationic X) 1.0 percent by weight bone glue 85.70 percent by weight water Procedure The oil modified alkyd resin, the polyglycol ester of a fatty acid, and the epoxy materials were combined in a mixing tank. Water was added slowly with agitation to form an oil-in-water emulsion and in amounts to make up about three-quarters of the total volume of the batch.

In a separate tank, the cationic X compound was dissolved in hot water at about 160 F. to form a 25% solution which was incorporated with mixing into the main tank containing the emulsion. The stearato chromic chloride was prepo-lymer-ized by adding it to three times its volume of boiling water and this mixture was then added to the emulsion. The final size composition had a pH of 3.5125, a specific gravity of about 1.0 and a solids content of about 9.3 percent by weight.

The size can be applied to the glass fibers in forming, as by a wiper pad or roll applicator as the formed filaments of glass are gathered together into a strand. After drying for about 12 hours, strands were twisted about three times per inch to form yarns. After yarn formation, the size was cured by heating for about 16 hours at 300 F.

The yarns formed in accordance with the practice of this invention were compared from the standpoint of various properties after having been coated with a plastisol to form a conventional gray coated yarn. Yarns prepared in accordance with the practice of this invention were compared with equivalent yarns from the standpoint of fiber diameter, fiber concentration and the number of fibers in the strand and the number of strands and twists in the yarn but in which a size composition of the type previously employed was present on the glass fiber surfialces. Yarns treated in accordance with Example 4 gave a dry fiexure strength of 11,055 pounds per square inch as compared to 7,800 pounds per square inch for yarns of the type heretofore produced. Yarns treated in accordance with Example 4 gave an abrasion value of 1,864 as compared with 962 for yarns sized with compositions of the type heretofore employed. In dry and wet breaking strengths, yams produced with the composition of Example 4 had a dry strength of 11.3 pounds and a wet strength of 10.2 pounds by comparison with values of 11.0 and 9.8 respectively, for previous systems.

An important advance in the practice of this invention resides in the ability, for the first time, successfully to make use of glass fibers of larger diameter and of considerably less cost in the manufacture of yarns which, when embodying the size compositions of the type described, have processing and performance characteristics equivalent to those heretofore produced with the more expensive fibers of lesser diameter and by way of example, present yarn formation of glass fibers has been mostly of the designation of 150 l/ 2 which relates to the number of yards of fibers multiplied by per pound of fiber or 15,000 yards per pound. Little success has heretofore been experienced in the use of fibers to produce yarns having the designation 75 1/0, which would be of considerably lower cost.

It has been found that the ability to fabricate yarns of 75 1/0 depends greatly upon the size composition applied to the glass fiber surfaces since yarns having the designation of 75 1/0 can be produced when size compositions embodying the features of this invention are employed. In fact, in many respects, yarns of greater strengths and improved processing and performance characteristics are secured with 75 1/0 yarns as compared with 1/2 yarns of the type heretofore employed in yarn manufacture.

By way of illustration, 150 1/2 yarns sized with the composition of Example 4 gave a dry flexure strength of 11,055 pounds per square inch, wet flexure strength of 1,708 pounds per square inch, breaking strength of 11.3 pounds dry and 10.2 pounds wet, whereas 75 1/0 yarns sized with the same composition gave corresponding values of 17,512 pounds per square inch for dry flexure, 4,250 pounds per square inch for wet flexure, 11.6 pounds for dry breaking strength, and 11.0 pounds for wet breaking strength.

In its broader concepts, the preferred composition embodying the features of this invention can be formulated to contain the corresponding materials with the following proportions given in percent by weight of the treating composition:

EXAMPLE The stearato chromic chloride, while notnecessary .in the size composition, functions as a coating to enhance the bonding relationship between the size coating on the glass, fiber surfaces and subsequently applied resinous materials while at the same time desirably providing a degree of lubricity by reason of its long chain group. Instead of the stearato chromic chloride, use can be made of stearysilsesquioxane. As anchoring agents, use can also be made of other materials incorporated as an additional component in the treating composition. Such other anchoring agents are capable of being represented by unsaturated organo silicon compounds in the form of silanes, their hydrolysis products (silanols) and their polymerization products (polysiloxanes) in which the silane is represented by vinyltrichloro silane, vinyltriethoxy silane, divinyldichloro silane, allyltriethoxy silane, styryltrichloro silane and the like organo silicon group in which an organic group attached directly to the silicon atom contains less than 8 carbon atoms in aliphatic arrangement and in which the aliphatic group contains an unsaturated ethylenic group. Use can also be made of Werner cornplex compounds in which the acido group coordinated with the trivalent nuclear chromium atom is also a short chained group having an unsaturated or ethylenic linkage, as represented by methacrylato chromic chloride. Cationicamine compounds can also be employed in which the organic group attached to the basic nitrogen atom is a short chained organic group containing a similar unsaturated or ethylenic linkage. When employed, such anchoring agent can be formulated to be present in an amount within the range of Oil-2J0 percent by weight of the treating composition.

'Instead of making use of an anchoring agent as a component in the size composition applied to the glass fiber surfaces, improved bonding between the size coating and the glass fiber surfaces can be achieved by the treatment of the glass fibers to provide a desired degree of surface roughness without destroying or undesirably affecting the properties of the glass fibers. Broadly defined, the method for treating glass fibers to impart a desired degree of surface roughness for enhancing physical anchorage as between the size coating and the glass fibers is the pre-treatment for the glass fibers with a composition containing silicic acid to deposit particles of silica in a strongly bonded relationship on the glass fiber surfaces. Use can also be made of such systems as in the treatment of the glass fiber surfaces with a titanium complex such as includes the titanium tetraesters.

Still further, use can be made of inorganic metal salts of aluminum hydroxide which, when applied to the glass fiber surfaces and dried, impart a roughness which appears as a part of the glass fiber surface to provide means for physical attachment. While description hereof for physical attachment has been indicated in connection with the separate treatment of the fibers in yarn formation, it will be understood that such means for producing surface roughness on glass fibers to provide a means for physical attachment will be applicable also to other combinations made of glass fibers such as with resinous adhesives, coatings, and binders in the manufacture of glass fiber reinforced plastics, laminates, coated fabrics, colored and coated fiber strands and yarns and the like which may be formed of continuous textile fibers or discontinuous wool fibers.

The following will illustrate further compositions:

EXAMPLE 6 15.0 percent by weight linseed oil 3.0 percent by weight chrome glue 0.3 percent by weight drier (lead cobalt zinc naphthenate) 0.5 percent by weight polyglycol ester of a fatty acid (polyethylene glycol ester of stearic acid) 0.5 percent by weight stearato chromic chloride 80.7 percent by weight water EXAMPLE 7 4.0 percent by weight epoxidized ricinoleate (P13-'- Bakers Castor Oil Company) 3.0 percent by weight chrome glue 3.0 percent by Weight stearato chromic chloride 1.0 percent by weight polyglycol ester of a fatty acid 89.0 percent by weight water EXAMPLE 8 4.0 percent by weight chrome glue 3.0 percent by weight fatty acid cationic amine lubricant 4.0 percent by weight bodied linseed oil 8.0 percent by weight polyethylene glycol (Carbowax 4000 81.0 percent by weight water EXAMPLE 9 EXAMPLE 10 6.0 percent by weight polyvinyl chloride latex (K-576 B. F. Goodrich Company) 15.0 percent by weight linseed oil 0.5 percent by weight drier 0.5 percent by weight arylalkyl polyether alcohol 5.0 percent by Weight stearato chromic chloride 83.0 percent by weight water EXAMPLE 1 1 10.0 percent by weight epoxy resin (Epon 828) 0.4 percent by weight polyvinyl alcohol 0.5 percent by weight sorbitan mono-oleate 0.3 percent by weight unsaturated organo silicon compound (XR-4191-Dow-Corning Corporation) 88.8 percent by Weight water EXAMPLE 12 5 .0 percent by weight poly-acrylic resin (Rhoplex AC33Rohm & Haas Co.) 5 .0 percent by weight raw linseed oil 0.15 percent by weight drier 0.15 percent by. weight fatty acid ester of polyhydric alcohol 3.0. percent by weight stearato chromic chloride 86.70 percent by weight water 7 EXAMPLE 13 An aqueous composition containing the following ingredients in percent by weight:

l-S percent by weight oil modifiedalkyd resin 1-5 percent by weight unpolymerized epoxy resin 0.1-3.0 percent by weight stearato chromic chloride 0.1-1.0 percent by weight gelatin 0.1-0.25 percent by weight glass fiber lubricant 0.l-2.0 percent by weight anchoring agent In Example 13, the anchoring agent is a Werner complex compound in which the organic group attached to the trivalent nuclear chromium atom contains less than 8 carbon atoms and an unsaturated ethylenic group, or an organo-silicon compound in which the organic group attached to the silicon atom contains less than 8 carbon atoms with an unsaturated ethylenic group or a cationic amine compound in which the organic group attached to the basic nitrogen atom contains 8 carbon atoms with an unsaturated ethylem'c group.

The components in the foregoing examples can be formulated to produce the size composition, as previously described with reference to Examples 1 to 4. Application onto the glass fibers can be made at room temperature, as by a wiper pad or roll applicator.

In the practice of this invention, the size is preferably cured after twisting but, if desired, it may be cured on the forming tube. If cured on the tube, it is desirable first to remove the moisture as by exposure of the tube to elevated temperature and preferably to dielectric heat. After drying, the size may be cured by heat treatment for about 12 hours at 300 F.

In the manufacture of a twisted yarn, the size is dried for about 12 hours at room temperature and then the size is advanced to a cured stage by heating on the twist tube for 6 hours at about 300 F. When so processed, it is desirable to pro-shrink the twist tube under the prevailing conditions as by preheating the tubes to 300 F. This will minimize slippage of the yarn after cure.

In the event that the yarn is to be plied, it is desirable to eliminate the curing step since such cure is not essential in a plied yarn to achieve a fuzz-free yarn. Without cure, still further improvements are secured in abrasion resistance. It has been found that in the absence of exposing the size to curing temperature, as in the order of 250 F. or higher, the binder will remain uncured even after standing for a month or more.

The advancement of the size to a cured stage activates the binder components of the size composition to impart good integrity to the bundle of fibers. Decrease in the rate of processing the sized yarn will result in lower flexure but increased stiffness. It is believed that this is caused by the advancement of the resinous components to a higher state of cure or because of the volatilization of larger amounts of plasticizers from the coating or combinations thereof.

It has been found that yarn construction has considerable influence on the adhesiveness of the size and the characteristics of the yarn. Adhesion appears to decrease in direct proportion to the number of twists in the yarn when more than four twists per inch are employed. When the number of twists exceeds four, the adhesion begins to fall off to the point where very little adhesion is available at eight twists per inch. In addition, when more than four twists per inch are employed, the yarn tends to be wild but with less than two twists, the yarn tends to flatten in the weaving.

From the foregoing, it will be apparent that we have succeeded in the formulation of a size composition for use in the manufacture of yarns of glass fibers wherein the size composition is formed of components which are capable of being easily and inexpensively combined to form a system of lower cost than size compositions heretofore employed and of greater stability. It will be apparent further that the size composition enables utilizat-ion of less expensive glass fibers in the manufacture of yarn structures having properties equivalent to if not better than yarns heretofore employed with more expensive binder fibers.

It Will be evident further that in the treatment of glass fibers with compositions of the type described for use in yarn formation, improvements are secured in the performance and processing characteristics of the glass fibers and in the yarns formed thereof whereby better prope ties are made available from the standpoint of strength and fiexure and from-the standpoint of the coatability of the yarns for use in the manufacture of braids, textiles and various insulation materials.

It will be understood that changes may be made in the details of construction, formulation and application without departing from the spirit of the invention, especially as defined in the following claims.

We claim:

1. A composition for use as a size applied to glass fibers for imparting the desired performance and processing characteristics in yarn construction comprising an aqueous system containing 1-5 percent by weight of an oil modified polyester resin, 0-5 percent by weight of a plasticizer for the polyester resin, 0.1-2 percent by Weight of an anchoring agent selected from the group consisting of a Werner complex compound, a cationic amine compound and an organo silicon compound in which the organic group attached to the trivalent nuclear chromium atom of the Werner complex compound and the organic group attached to the basic nitrogen atom of the cationic amine compound and the organic group attached to the silicon atom of the organo silicon compound contains less than 8 carbon atoms with an unsaturated eythlenic group, 0-3 percent by weight of a chrome complex in which the acido group coordinated with the trivalent nuclear chromium atom contains more than 8 carbon atoms, and 0.1-1.0 percent by weight of a hydrophilic colloid.

2. A composition for use as a size applied to glass fibers for imparting the desired performance and processing characteristics in yarn construction comprising an aqueous system containing 1-5 percent by weight of an oil modified alkyd resin, 0-5 percent by weight of a plasticizer for the oil modified alkyd resin, 0-3 percent by weight of a chrome complex compound in which the acido group coordinated with the trivalent nuclear chromium atom contains more than 8 carbon atoms, and 0.1-1.0 percent by weight of a hydrophilic colloid.

3. A composition for use as a size applied to glass fibers for imparting the desired performance and processing characteristics in yarn construction comprising an aqueous system containing 1-5 percent by weight of an oil modified alkyd resin, 0-5 percent by weight of a plasticizer for the oil modified alkyd resin, 0-3 percent by weight of a chrome complex compound in which the acido group coordinated with the trivalent nuclear chromium atom contains more than 8 carbon atoms, and 0.1-1.0 percent by Weight of gelatin.

4. A composition for use as a size applied to glass fibers for imparting the desired performance and processing characteristics in yarn construction comprising an aqueous system containing 1-5 percent by weight of an oil modified alkyd resin, 0.5 percent by weight of a plasticizer for the oil modified alkyd resin, 0-3 percent by weight of a chrome complex compound in which the acido group coordinated with the trivalent nuclear chromium atom contains more than 8 carbon atoms, and 0.1-1.0 percent by weight of a water soluble glass fiber softener and lubricant.

5. A composition for use as a size applied to glass fibers for imparting the desired performance and processing characteristics in yarn construction comprising an aqueous system containing 1-5 percent by weight of an oil modified alkyd resin, 0-5 percent by weight of an unpolymerized epoxy resin, 0-3 percent by weight of a chrome complex compound in which the acido group coordinated with the trivalent nuclear chromium atom contains more than 8 carbon atoms, and 01-10 percent by weight of a hydrophilic colloid.

6. A composition for use as a size applied to glass fibers for imparting the desired performance and processing characteristics in yarn construction comprising an aqueous system containing 1-5 percent by weight of an oil modified alkyd resin, 0.5 percent by weight of a plasticizer for the oil modified alkyd resin, -3 percent by weight stearato chromic chloride, and 01-10 percent by weight of a hydrophilic colloid.

7. A composition for use as a size applied to glass fibers for imparting the desired performance and processing characteristics in yarn construction comprising an aqueous system containing 1-5 percent by weight of an oil modified alkyd resin, 1-5 percent by weight of an unpolymerized epoxy resin, 0.1-3.0 percent by weight stearato chromic chloride, 01-10 percent by weight gelatin, and 0.1-0.25 percent by weight of a glass fiber lubricant.

8. A composition for use as a size applied to glass fibers for imparting the desired performance and processing characteristics in yarn construction comprising an aqueous system containing 1-5 percent by weight of an oil modified alkyd resin, 1-5 percent by weight of an unpolymerized epoxy resin, 0.1-3.0 percent by weight stearato chromic chloride, 0.1-1.0 percent by weight gelatin, 01-025 percent by weight of a glass fiber lubricant and (1.1-2.0 percent by weight of an anchoring agent se lected from the group consisting of a Werner complex compound, a cationic amine compound and an organo silicon compound in which the organic group attached to the trivalent nuclear chromium atom of the Werner complex compound and the organic group attached to the basic nitrogen atom of the cationic amine compound and the organic group attached to the silicon atom of the organo silicon compound contains less than 8 carbon atoms with an unsaturated ethylenic group.

9. A yarn comprising glass fibers and a cured coating on the glass fiber surfaces comprising 1-5 parts by weight of a cured oil modified alkyd resin, 0-5 parts by weight of a plasticizer for the oil modified alkyd resin, 0-3 parts by weight of a chrome complex compound in which the acido group coordinated with the trivalent nuclear chromium atom contains more than 8 carbon atoms and 0.1-1.0 part by weight of a hydrophilic colloid.

10. A yarn comprising glass fibers and a cured coating on the glass fiber surfaces comprising 1-5 parts by weight of a cured oil modified alkyd resin, 1-5 parts by weight of an unpolymerized epoxy resin, 0. 1-3 .0 parts by weight of stearato chromic chloride, 0.1-1.0 part by weight of gelatin and 0.1-0.25 part by weight of a glass fiber lubricant.

11. The method of producing yarns of glass fibers comprising coating the fibers in forming with a composition comprising 1-5 percent by weight of an oil modified alkyd resin, 0-5 percent by weight of a plasticizer for the oil modified alkyd resin, 0-3 percent by weight of a chrome complex compound in which the acido group coordinated with the trivalent nuclear chromium atom contains more than 8 carbon atoms, and 0.1-1.0 percent by weight of a hydrophilic colloid, gathering a plurality of the coated fibers together into endless bundles, drying the bundles of coated glass fibers at about room temperature, processing 10 the dried bundles of glass fibers by the steps which include twisting and plying to form yarns, and heating the yarns of glass fibers to an elevated temperature for a time suflicient to advance the coating to a cured stage.

12. The method of producing yarns of glass fibers comprising coating the fibers in forming with a composition comprising 1- 5 percent by weight of an oil modified alkyd resin, 0-5 percent by weight of a plasticizer for the oil modified alkyd resin, 0-3 percent by weight of a chrome complex compound in which the acido group coordinated with the trivalent nuclear chromium atom contains more than 8 carbon atoms, and 0.11.0 percent by weight of a hydrophilic colloid, gathering a plurality of the coated fibers together into endless bundles, drying the bundles of coated glass fibers at about room temperature, processing the dried bundles of glass fibers by the steps which include twisting and plying to form yarns, and heating the yarns of glass fibers to a temperature within the range of 250-350 F. for a time sufiicient to advance the coating to a cured stage.

13. The method of producing yarns of glass fibers comprising coating the fibers in forming with a composition comprising 1-5 percent by weight of an oil modified alkyd resin, 1-5 percent by weight of an unpolymerized epoxy resin, 0.1-3 .0 percent by weight stearato chromic chloride, 01-10 percent by weight gelatin, and 01-025 percent by weight of a glass fiber lubricant, gathering a plurality of the coated fibers together into endless bundles, drying the bundles of coated glass fibers at about room temperature, processing the dried bundles of glass fibers by the steps which include twisting and plying to form yarns, and heating the yarns of glass fibers to an elevated temperature for a time suflicient to advance the coating to a cured stage.

14. The method of producing yarns of glass fibers comprising coating the fibers in forming with a composition comprising 1-5 percent by weight of an oil modified alkyd resin, 1-5' percent by weight of an unpolymerized epoxy resin, 01-30 percent by weight stearato chromic chloride, 0.11.0 percent by weight gelatin, and 0.1-0.25 percent by weight of a glass fiber lubricant, gathering a plurality of the coated fibers together into endless bundles, drying the bundles of coated glass fibers at about room temperature, processing the dried bundles of glass fibers by the steps which include twisting and plying to form yarns, and heating the yarns of glass fibers to a temperature within the range of 250-350 F. for a time sufiicient to advance the coating to a cured stage.

References Cited in the file of this patent UNITED STATES PATENTS 

9. A YARN COMPRISING GLASS FIBERS AND A CURED COATING ON THE GLASS FIBER SURFACES COMPRISING 1-5 PARTS BY WEIGHT OF A CURED OIL MODIFIED ALKYD RESIN, 0-5 PARTS BY WEIGHT OF A PLASTICIZER FOR THE OIL MODIFIED ALKYD RESIN, 0-3 PARTS BY WEIGHT OF A CHROME COMPLEX COMPOUND IN WHICH THE ACIDO GROUP COORDINATED WITH THE TRIVALENT NUCLEAR CHROMIUM ATOM CONTAINS MORE THAN 8 CARBON ATOMS AND 0.1-1.0 PART BY WEIGHT OF A HYDROPHILIC COLLOID. 